Make vectorizer to use max_loop_iterations_int

Make vectorizer to use max_loop_iterations_int

[Jan Hubicka]

Hi,
this patch makes vect_analyze_loop_2 to give up on loops with low max iteration
counts (instead of only considering estimated_stmt_executions_int).  This
change was eaerlier approved by Richi in stage4 and reverted.
I got wrong the testm instead == -1 there was != -1 and thus the regressions.
Noticed that only now.

Bootstrapped/regtested x86_64-linux, comitted.

Honza

Index: ChangeLog
===================================================================
--- ChangeLog	(revision 236477)
+++ ChangeLog	(working copy)
@@ -1,3 +1,8 @@
+2016-05-19  Jan Hubicka  <hubicka@ucw.cz>
+
+	* tree-vect-loop.c (vect_analyze_loop_2): Use also 
+	max_loop_iterations_int.
+
 2016-05-19  Marek Polacek  <polacek@redhat.com>
 
 	PR tree-optimization/71031
Index: tree-vect-loop.c
===================================================================
--- tree-vect-loop.c	(revision 236450)
+++ tree-vect-loop.c	(working copy)
@@ -2065,6 +2065,8 @@ start_over:
 
   estimated_niter
     = estimated_stmt_executions_int (LOOP_VINFO_LOOP (loop_vinfo));
+  if (estimated_niter == -1)
+    estimated_niter = max_niter;
   if (estimated_niter != -1
       && ((unsigned HOST_WIDE_INT) estimated_niter
           <= MAX (th, (unsigned)min_profitable_estimate)))